A Collection of Chiggers (Acarina: Trombiculidae) from Rodents in Southwestern Colombia

Abstract

Eighteen species of chiggers (eight new) are recorded from southwestern Colombia, south of Cali and west of Popayan. New species and their type hosts are: Odontacarus munchiquensis off Oryzomys albigularis, Polylopadium tertium off Heteromys australis, Pseudoschoengastia oopsi off Thomasomys fuscatus, Euschoengastia colombiana off Oryzomys albigularis, Euschoengastia pamelae off Thomasomys cinereiventer, Euschoengastia pichindensis off Oryzomys caliginosus, Euschoengastia trapidoi off Oryzomys caliginosus, and Trombicula almae off Oryzomys albigularis. Corrections are given for the descriptions of Intercutestrix tryssa and Vanidicus tricosus. Supplemental to repeated isolations of a new virus of the Tacaribe group from Oryzomys albigularis in the mountain valley of the Pichinde river near Cali, Colombia, ectoparasites of this and related rodents were collected for identification as the initial step toward determining whether the agent might be transmitted by arthropods. Field and laboratory studies were under the direction of Dr. Carlos Sanmartin, Universidad del Valle and Dr. Harold Trapido, Rockefeller Foundation. This report is based on 90 lots of 18 species (or forms) of chiggers, of which eight are described as new. All were collected from January to June 1967, 81 from several fincas (El Cairo, La Esperanza, La Flora, La Playa, Santa Marta), Pichinde valley, Municipio de Cali, Departamento del Valle, and nine from five locations 60 km west of Popayan, Departamento del Cauca. Holotypes are deposited in the Rocky Mountain Laboratory (RML), available paratypes there, in the United States National Museum (USNM), Field Museum of Natural History (FMNH), and British Museum (Natural History) (BMNH). Odontacarus munchiquensis, sp. n. (Fig. 1) Type data: Holotype, RML 47752, off Oryzomys albigularis, Pefia del Perro, 2,180 m, Departamento del Cauca, in vicinity of Cerro Munchique, 60 km west of Popayan, 11 May; 10 paratypes off 4 Thomasomys cinereiventer, Sitios Nos. 1, 2, 3, 2,500 m, Pefia del Perro, same general location as above, 5-12 May. Holotype, RML; paratypes RML, USNM, BMNH, FMNH. Received for publication 20 February 1968. Diagnosis: Mastitarsala III apparently absent (at least not found among the 11 specimens of the series), no parasubterminala, no genualae II and III, but a microgenuala II, sensilla barbed. Differs from the Panamanian 0. fieldi by the much larger cheliceral teeth, twice as many (about 80) dorsal setae, and no mastitarsala III. Body: Broad-ellipsoidal. Eyes prominent, 2/2 in a plate. Length and width of holotype, slightly engorged, 561 by 490 ,u. Anus at third row of ventral setae. Spiracles and tracheae conspicuous. Gnathosoma: Puncta small, numerous. Blades large, with large teeth increasing in size posteriorly, 6 to 8 dorsally, 16 to 20 ventrally. Palpal setae B/B/BBB, lateral seta sometimes nude; tarsus with 7 branched setae and a tarsala; claw trifurcate. Galeal seta nude. Scutum: As figured for holotype, but some specimens with less angulate posterior margin; puncta conspicuous, moderately abundant; sensilla weakly barbed, setae with strong, coarse barbs. Measurements of holotype: AW 90, PW 113, SB 37, ASB 42; PSB 21, AP 28, AM 59, AL 65, PL 95, S 106. Legs: Moderately punctate. Specialized setae as figured, a microgenuala II, no parasubterminala or mastitarsala III. Nonspecialized setae densely branched. Body setae: Dorsal setae about 80, similar to scutals, 45 to 80 A, increasing in length laterally and posteriorly. Ventral setae two sterals plus about 80, postanals similar to but somewhat shorter than dorsals. Polylopadium tertium, sp. n. (Fig. 2) Type data: Holotype and 2 paratypes, RML 47734, off Heteromys australis, La Flora, 1,900 m, 11 March. Holotype, RML; paratypes USNM, BMNH. Diagnosis: Scutum posteriorly produced to form a pseudoscutum which includes 17 platelets and 10 dorsal setae. Differs from the other two members of the genus, kramisi and confirmatum, in having 3 pairs of sternal setae and lacking a tibiala III. Body: Circular. Eyes tiny, probably 2/2, but the posteriors obsolescent. Anus posterior to last